Identify and define testing needed to minimize process design risks for a new waste treatment system designed to treat a complex mixture of nuclear waste.
As a follow-on project to the TRU-LWTD conceptual design, the client, a government facility contractor, contracted Process Engineering Associates, LLC (PROCESS) to identify testing that should be performed in order to reduce project risk. During the execution of the design of a system to process high-level transuranic radioactive waste, a number of key assumptions were made that are difficult to validate. Many important properties and characteristics of the waste feed and concentrate streams that influence the design and operability of the system were not fully known. Although these properties, characteristics, and design features were estimated using chemical process simulation software and first principles of chemistry, or developed based on experience with similar, though not identical, waste streams and operations, it was deemed necessary to perform testing to validate the assumptions. Predicting the behavior of complex processes involving mixtures of chemicals and solids is very challenging, and testing to validate derived properties is desired to address gaps in process knowledge and to reduce project risk.
Specific tasks for this project included:
- Development of a matrix of proposed tests with their desired objectives, data to be collected, and justification of the tests, with the tests ranked by priority based on the importance of the information expected to be obtained by the specific tests and when the information would be needed by the design team to meet project milestones.
- Development of a test procedure to validate physical properties and solids precipitation and behavior of various streams that were predicted by CHEMCAD and OLI process simulation software.
- Development of a test procedure to validate performance parameters and physical design features of the waste evaporators in order to achieve the desired heat transfer, volume reduction of the waste, and decontamination factor of the condensate. This test is to be performed using full scale equipment and surrogate solutions in a complete system, including feed tank, evaporator, condenser, condensate tank, concentrate tank, pumps, piping, and instrumentation. Multiple waste stream surrogates and multiple evaporator configurations will be tested.
- Development of a test procedure to develop and validate the configuration and process parameters of an air sparge mix system to be utilized in the waste concentrate tanks. A uniform mixture is required in the concentrate tanks in order to properly characterize the waste before disposal. This test is to be performed using full-scale equipment and surrogate solutions in a complete system, including a concentrate tank, a configurable air sparge system, and instrumentation. Multiple waste stream surrogates and multiple air sparger configurations will be tested.
- Development of a test procedure to develop and validate the configuration and process parameters of a steam jet transfer system to be utilized to transfer waste solutions. This test is to be performed using full-scale equipment and surrogate solutions in a complete system, including a source tank, a steam jet, tank mixer, receiver tank, and instrumentation. Multiple waste stream surrogates and multiple steam pressure and jet configurations will be tested.
The project tasks were completed under budget and on a schedule that fully supported the project team’s other tasks and goals.
- Nuclear Waste Processing
- Process design risk identification and mitigation
- Process validation test planning